1. Field of the Invention
The present invention pertains to apparatus for mechanically sorting fruit, and more particularly, it pertains to deflecting apparatus for selectively diverting falling fruit into a desired trajectory.
2. Description of the Prior Art
Colorimetry, i.e., the analysis of an object upon the basis of its color has been used in a variety of apparatus for sorting fruit and vegetables according to color. Color sorting apparatus which has been specifically designed for the sorting of fruits or vegetables generally provides some means for measuring the reflectance property of the fruit or vegetable being tested. The reflectance of a surface is a measure of the percentage of incident light reflected by it, and colored objects have different reflectances for light of different wavelengths. The relationship between reflectance and the illuminating wavelength of a fruit being tested will produce a characteristic curve which can then be used in the design of apparatus and circuitry for color sorting that fruit. That is to say, a fruit may be classified as to color by suitably measuring, describing and classifying its reflectance curve, and food may be sorted into different grades by denoting the differences between the reflectance curves for the various grades and testing for these differences.
Signals from two or more photoelectric cells, each of which measures the quantity of light reflected in a different wavelength have been used to determine that fruit is ripe, or too green, or overripe. Any signal developed due to a green or, perhaps, due to an overripe fruit will be directed to a reject mechanism which will divert the cull fruit to a separate discharge location.
Despite the development of such mechanical sorting means, field harvesting vehicles (such as tomato harvesters) have not generally used them heretofore due to the difficulties of successfully sorting under field conditions as opposed to packing house conditions. In prior art field harvesters the sorting was generally done by human operators who stand on a platform adjacent moving conveyor belts carrying the produce, pick up the cull fruit, and manually discharge them as the harvester moves across the field. This prior art method of sorting tomatoes, for example, is expensive due to the number of people needed to sort the fruit on the moving conveyor belts. The efficiency and accuracy of the sorting is dependent upon the people involved so that the quality of the sorting varies with different individuals and with different times of the day. After prolonged periods of sorting, the human sorter may become tired and not do a good job. What has been needed is apparatus that can perform sorting of tomatoes or other fruit at a lower cost and in a more consistent manner than in prior art harvesters.
Mechanical sorting of objects such as fruit has been carried out by devices which permit the fruit to gravitate between a pair of conveying means with a selectively actuatable diverter, under the control of the color scanning means, being positioned at the gap between the conveying means to divert the rejected fruit from its normal trajectory. Such diverters have been comprised of air blast devices, which can be messy and ineffective if soft fruit is encountered, or power-actuated paddles. The paddles have been moved by solenoid devices and pneumatic or hydraulic cylinders. Such mechanisms are shown, for example, in U.S. Pat. Nos. 3,381,819 to Crawford, 3,581,888 to Kelly et al, 3,489,277 to Silverman, and 3,675,769 to Story. Despite the widespread use of selectively actuatable diverting mechanisms for use in sorting operations, no wholly suitable diverting device has heretofore been provided which can operate under the conditions imposed by field sorting operations where speed of operation is essential and wherein significant size and weight differences exist between the fruit or foreign objects (e.g., dirt clods) being scanned.